Question

An infinite number of ratios are equivalent to 3:8. How can that be possible, when the multiplication table only goes to 9?

Answer 1

A multiplication table only shows low multiples that a person could do in their head. It does not contain every possible multiple. For higher multiples, it is expected for a person to use a calculator.

For the ratio 3:8, you can multiply both 3 and 8 by any number (could be 2, could be 153, could be 9273719, etc.) and the ratio would be equal.